Barbara Ciżkowicz Comparison of short forms of the Social Interaction Anxiety Scale and the Social Phobia Scale: psychometric properties of the scales in a Polish sample

Abstrakt

The Social Interaction Anxiety Scale (SIAS) and the Social Phobia Scale (SPS) are commonly used scales to measure social anxiety. These scales have satisfactory psychometric properties. However, due to their length (i.e. 39 items), shortened versions of these scales have been developed. The most commonly used are two 12-item versions developed by two different teams of researchers. 

The aim of the study was to assess the psychometric properties of the two short forms of the SIAS and the SPS and to compare their usefulness in a Polish non-clinical sample. 

Analyses were conducted on a sample of 698 adults (M=26.1; SD=8.2; 55% female). Factor structure, internal consistency, and content, criterion convergent and discriminant validity were assessed. Confirmatory factor analysis (CFA) was used to determine construct structure. Measurement invariance was examined across gender and age. Reliability was assessed using Cronbach's alpha. 

The reliability of the scales was high. All Cronbach's alpha coefficients were > 0.78. The CFA confirmed the two-factor structure of both short forms of the scales. Model fit indices were good for the Peters et al. short form, and acceptable for the Peters et al. short form. Measurement invariance across subjects' gender and age for both short forms of the SIAS-6+SPS-6 confirmed configural, metric and scalar invariance. 

These results prove that both short forms of the scales have fully satisfactory psychometric properties including confirmed measurement invariance across gender and age and can be used in research and screening studies in adults and adolescents.